IPv6 is coming...it is just a matter of time. In addition to the massive increase in IP addresses it also has an expanded header that will tag the packet as being voice, video or data which will allow for prioritization of the packet...which will lead to voice and video over IP that should work well.

Having said that before it can happen every router will need to be IPv6 compatible......so it will be a while but the applications are driving the change and it will happen.